The dependency on Docker only exists for when you want to turn your shell into a container – but it's not otherwise used when you're just running a shell locall

The dependency on Docker only exists for when you want to turn your shell into a container – but it's not otherwise used when you're just running a shell locally. When writing javascript there's often a desire to have "isomorphic" or "universal" applications. Write the code once and run it in _either_ the client or the _server_. Devbox is taking a similar approach to the development environment: declare it once, run it locally as a shell, and when you're ready, turn it into a container without having to re-declare it. It's only the latter functionality that has a Docker dependency.